Unprotected R123s - **NOT** RECOMMENDED

[Jefff]

Re: High-cap unprotected R123s - first impressions

Hey Kevin.. I'm working on a deal to test out the PentagonLight X2 with a X3 9V head to be used with the R123's.. in about 2 weeks time or so I should be recieving some more info and the parts to test..I will be doing a full review on this setup and post it here on the CPF site for all too see.. but could ya let me know as soon as there is another shipment of the r123's in stock so that I can purchase a set with the charger.. Thanks Email me if you happen to get a chance. to let me know how your results are going on the stacking using 2 or more of these cells in series project to power the p90/91..This is the very same setup I will be using with mine..
alternate email is [email protected]
or just use the one on my profile.. Thanks Jeff

BTW Great post your a very helpful person indeed! Thanks again

 

[vcal]

Re: High-cap unprotected R123s - first impressions

KevinL;
Your voltage crash can sometimes mitigated -if you have a way to apply a low D.C. current (25-50mA from a filtered power supply) to the cell when it was at the 1.9 volt level.

The technique is to bring it up to 3 volts with the low current, and then complete the charge with the regular charger.

This helps if the cell hasn't been too severely abused already. I've found that the sudden drop-off in voltage is fairly dramatic -beginning at about the 3.3 volt (open circuit) level.

p.s.-you will know if that technique didn't help, -if your cell only charges up a few more times (4-5) and then decides all of a sudden to quit accepting a charge. /ubbthreads/images/graemlins/icon15.gif

 

[KevinL]

Re: High-cap unprotected R123s - first impressions

Jeff: It's going pretty well. For more important stuff, I prefer the JSB protected R123s since they can tolerate a little less careful handling. Project C2-90 has been running on those for quite a while now and there are no long term drawbacks other than when the batteries are exhausted, the light goes out abruptly.

The advantage of the unprotected cells is that they can tolerate a lot higher current drains than the protected cells. A P91 that will not light AT ALL with protected cells performs wonderfully with unprotected cells. I've done about 4 full discharges of the P91, very impressed except for the voltage problems. If you discharge a R123 below 2.5V you risk damaging it, severely. It's very easy to reach this dangerous-discharge level without realizing it as I am finding out.

vcal: thanks for the tip. What I do is throw the cells back into the charger immediately. As little as 30 seconds will bring a cell back to 3.3V from the dangerous zone, I'm hoping I'm in time to prevent any long term damage. If not, I'll just write it off as part of the learning curve.

Speaking of the learning curve, I was using one of the unprotected R123s to direct-drive a Luxeon star while doing some testing. Two of the wires brushed together, causing a dead short while I was holding the other ends against the R123. Needless to say it was a tiny fraction of a second, but my fingers hurt like H@LL now.

 

[Jefff]

Re: High-cap unprotected R123s - first impressions

[ QUOTE ]
Jeff: It's going pretty well. For more important stuff, I prefer the JSB protected R123s since they can tolerate a little less careful handling. Project C2-90 has been running on those for quite a while now and there are no long term drawbacks other than when the batteries are exhausted, the light goes out abruptly.


[/ QUOTE ]

Do you happen to have a link to the JSB protected r123's?

Thank ya much on the info.. I will try Both if possible... Killing batts doesn't sound too good though .. so maybe just go with the protected ones with my tests.. thanks again .. in the mean time, I will do a search on the JSB protected R123's to see if i can find a link to them on here and google as well ..

 

[KevinL]

Re: High-cap unprotected R123s - first impressions

http://www.jsburlys.com/ for the protected R123s. They may or may not show up on the shopping cart due to stock availability, you'll have to send a PM to JonSidneyB about when they'll be available. He's the one who knows them best.

The disadvantage of unprotected R123s is that you must handle them with a lot of care. Overdischarge can kill the cells, overcharge can cause explosions/fires, and dead shorts can kill or maim fingers (as I discovered last night /ubbthreads/images/graemlins/crazy.gif). Fortunately the fingers feel a lot better by today.

Protected cells do away with all of this - none of this is a consideration with them. The only limitation with protected cells is that you cannot drive extremely high current devices with them - Surefire P91s running at 2.3A are no-go on those. However, this is technically overdischarging them (the cells aren't supposed to be able to tolerate this kind of discharge rate continuously).

Bottom line: protected cells for peace of mind. Unprotected cells for raw, in-yer-face performance. I'll keep both kinds around /ubbthreads/images/graemlins/smile.gif

 

[Jefff]

Re: High-cap unprotected R123s - first impressions

Gotcha .. thanks very much for the link .. take care and good luck on the test.. I hope all goes well for the both of us ..

 

[KevinL]

Re: High-cap unprotected R123s - first impressions

Thanks for the best wishes.. unfortunately it wasn't too long before I discovered that they're really not my style - Lithium ion explodes - I'm nearly hit

 

[Jefff]

Re: High-cap unprotected R123s - first impressions

ok then .. so im gonna go with the protected r123's lol, glad your ok .. I wonder what exactly caused that.. if it had anything to do with modding the charging voltage? or if it was just a faulty charger.. non the less Im still going to apt for the protected ones.. thanks for the info and again glad to hear no harm was done other than the charger... Jeff

 

[KevinL]

Re: High-cap unprotected R123s - first impressions

Thanks... There is always the possibly that tweaking the charger affected something - perhaps some component not up to spec to deliver the required voltage? It worked before for a couple of times but I'm aware that is no guarantee of it continuing to work. I can't conclusively point fingers and say "it's the pot's [and operator's] fault", but neither can I say "it's not".

Jon just got back to me and says the new batch of protected R123s will be a while because they are trying to make some improvements. The impression of the protected cells I have is that they work well, they just don't look good and there have been a few rejects in the first batch. I'm sure he's taking that up with them and making them get it right the second time round. This can only be a good thing for those of us counting on them.

 

[brightnorm]

Re: High-cap unprotected R123s - first impressions

[ QUOTE ]
cy said:
at 3.8V your R123 cell is aprox. 2/3 charged

[/ QUOTE ]

I used to think my PILAs were being undercharged since they never exceeded 3.87v right off charger, but as soon as I apply a load for only a second or two they shoot up to 4.12-4.15v and stay there.

As a non-techie I only use protected Li-ONs

Brightnorm

 

[Darell]

Re: High-cap unprotected R123s - first impressions

[ QUOTE ]
Halibut said:
Inquiring minds want to know. It seems silly that the manufacturer would ship a product that can't be used to its full potential--there must be a good reason for the 3.8V cutoff, right? Anyone? Darrell?


[/ QUOTE ]
Me? Yikes! I'm *not* a battery guy - beyond battery electric vehicles, that is. Here's the little bit that I do know about Li-ion in regard to this issue AND in regard to vehicle packs: Charging them to 100% reduces their cycle life. Significantly. If you never go to 100%, the batteries will *almost* last indefinitely. The one EV builder that is currently testing Li-ion packs will make the default charge termination at about 85% SOC. If you NEED the extra range, you can override that for a full charge. But to go to 100% every time when you don't need a full 300 miles of range is like dropping just a little bit of sand in the oil pan at every fillup. Charging any of the newer chemistries (NiMH, Li-ion) to the top is what will shorten their life more than any other treatment.

So... since you asked - that's what I think I might know about the subject.